Package ptolemy.actor.lib.string

Source Code of ptolemy.actor.lib.string.StringMatches

/* Pattern match a string to a regular expression.

Copyright (c) 2003-2005 The Regents of the University of California.
All rights reserved.
Permission is hereby granted, without written agreement and without
license or royalty fees, to use, copy, modify, and distribute this
software and its documentation for any purpose, provided that the above
copyright notice and the following two paragraphs appear in all copies
of this software.

IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.

THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
ENHANCEMENTS, OR MODIFICATIONS.

PT_COPYRIGHT_VERSION_2
COPYRIGHTENDKEY

*/
package ptolemy.actor.lib.string;

import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

import ptolemy.actor.TypedAtomicActor;
import ptolemy.actor.TypedIOPort;
import ptolemy.actor.parameters.PortParameter;
import ptolemy.data.BooleanToken;
import ptolemy.data.StringToken;
import ptolemy.data.expr.SingletonParameter;
import ptolemy.data.type.BaseType;
import ptolemy.kernel.CompositeEntity;
import ptolemy.kernel.util.Attribute;
import ptolemy.kernel.util.IllegalActionException;
import ptolemy.kernel.util.NameDuplicationException;

//////////////////////////////////////////////////////////////////////////
//// StringMatches

/**
Pattern match a string to a regular expression and output a true if it
matches and a false if it does not. For a reference on regular
expression syntax see:
<a href="http://java.sun.com/docs/books/tutorial/extra/regex/index.html">
http://java.sun.com/docs/books/tutorial/extra/regex/index.html</a>.

@author Antonio Yordan-Nones, Colin Cochran (contributor Edward A. Lee)
@version $Id: StringMatches.java,v 1.19 2005/07/08 19:56:37 cxh Exp $
@since Ptolemy II 4.0
@Pt.ProposedRating Green (djstone)
@Pt.AcceptedRating Green (eal)
*/
public class StringMatches extends TypedAtomicActor {
    /** Construct an actor with the given container and name.
     *  In addition to invoking the base class constructors, this constructs
     *  the <i>pattern</i> and <i>matchString</i> PortParameters,
     *  and the <i>output</i> port.
     *  @param container The container.
     *  @param name The name of this actor.
     *  @exception IllegalActionException If the actor cannot be contained
     *   by the proposed container.
     *  @exception NameDuplicationException If the container already has an
     *   actor with this name.
     */
    public StringMatches(CompositeEntity container, String name)
            throws NameDuplicationException, IllegalActionException {
        super(container, name);

        // Create one matchString portParameter, one matchString port,
        // and one output port.
        pattern = new PortParameter(this, "pattern");
        pattern.setStringMode(true);
        pattern.setExpression("");
        (new SingletonParameter(pattern.getPort(), "_showName"))
                .setToken(BooleanToken.TRUE);

        matchString = new PortParameter(this, "matchString");
        matchString.setStringMode(true);
        matchString.setExpression("");
        (new SingletonParameter(matchString.getPort(), "_showName"))
                .setToken(BooleanToken.TRUE);

        output = new TypedIOPort(this, "output", false, true);
        output.setTypeEquals(BaseType.BOOLEAN);
    }

    ///////////////////////////////////////////////////////////////////
    ////                     ports and parameters                  ////

    /** The string to be pattern matched to the regular expression.
     */
    public PortParameter matchString;

    /** Output is true if the pattern exists in the string, false otherwise.
     *  Its type is boolean.
     */
    public TypedIOPort output;

    /** The regular expression to be pattern matched with the
     *  matchString string.
     *  Its default parameter is an empty string that matches no strings.
     */
    public PortParameter pattern;

    ///////////////////////////////////////////////////////////////////
    ////                         public methods                    ////

    /** Override the base class to compile the regular expression if
     *  it has changed.
     *  @param attribute The attribute that changed.
     *  @exception IllegalActionException If the pattern cannot be compiled
     *  into a regular expression.
     */
    public void attributeChanged(Attribute attribute)
            throws IllegalActionException {
        if (attribute == pattern) {
            try {
                String patternValue = ((StringToken) pattern.getToken())
                        .stringValue();
                _pattern = Pattern.compile(patternValue);
            } catch (PatternSyntaxException ex) {
                String patternValue = ((StringToken) pattern.getToken())
                        .stringValue();
                throw new IllegalActionException(this, ex,
                        "Failed to compile regular expression \""
                                + patternValue + "\"");
            }
        } else {
            super.attributeChanged(attribute);
        }
    }

    /** Pattern match a regular expression against a supplied
     *  matchString and output a true if they match and a false
     *  otherwise.
     *  @exception IllegalActionException If there is no director.
     */
    public void fire() throws IllegalActionException {
        super.fire();
        pattern.update();
        matchString.update();

        String matchStringValue = ((StringToken) matchString.getToken())
                .stringValue();
        Matcher match = _pattern.matcher(matchStringValue);
        output.send(0, new BooleanToken(match.find()));
    }

    ///////////////////////////////////////////////////////////////////
    ////                         private variables                 ////
    // The pattern for the regular expression.
    private Pattern _pattern;
}
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